1. Field of the Invention
The present invention relates to cosmetic compositions and, more particularly to whitening cosmetic compositions for enhancing a whitening effect of the skin.
2. Brief Description of the Prior art
A variety of whitening cosmetics have been proposed or investigated and developed in order to remove spots such as stains, freckles, etc. appearing on the skin and to exhibit a whitening effect on the skin as a whole.
In the past, peroxides such as hydrogen peroxide, zinc peroxide, magnesium peroxide, sodium peroxide, zinc perborate, etc. were formulated in cosmetic compositions. However, these peroxides involve difficulties in storability and adaptability to formulating them in cosmetics because they are extremely unstable substances. Further, their whitening effect was unsatisfactory. Then, cosmetics in which vitamin C, cystein, colloidal sulfur, etc. are formulated were employed but they were still unsatisfactory.
In recent days, it has been reported that kojic acid obtained by cultivation of bacteria such as koji mold, etc. has an effect of rendering the skin fair as a whitening component for the whitening cosmetics. Whitening cosmetic using kojic acid are known in, for example, Published Examined Japanese Patent Application No. 18569/81 and Published Unexamined Japanese Patent Application No. 3538/78. Further, derivatives of kojic acid have been investigated and cosmetics containing kojic acid derivatives are known, for example, as shown in Published Unexamined Japanese Patent Application Nos. 7710/81, 7776/81 and 79616/81. Furthermore cosmetics containing pyrone compounds, chromone compounds or flavonol compounds are known, for example, as shown in Published Unexamined Japanese Patent Application Nos. 3538/78, 92305/80, 111410/80, 111411/80, 143908/80, 157580/80, 14517/82, 35506/82, 131911/83, etc.
Further, cosmetics in which placenta extracts are formulated are disclosed, for example, in Published Examined Japanese Patent Application No. 15399/60.